The dream of using solar panels in space to deliver electricity to the Earth below has animated engineers for 80+ years, but even with the falling cost of space access, we’re still far from solving the climate change problem with orbital power plants.
A new study from NASA evaluated whether Space Based Solar Power (SBSP) could compete with terrestrial electricity and reduce emissions. The authors considered two model designs that would both require putting massive arrays of solar panels in orbit to collect solar power and beam it to Earth.
First, the bad news: The technology won’t be ready for prime time by 2050, according to the study. And the SBSP that is available comes with a hefty pricetag—the cheapest electricity from space in their analysis is $0.61 per kilowatt-hour, while the average American pays $0.167 per kilowatt-hour today.
For those more worried about climate impact than dollar signs, the tech may not be as clean as it seems. While the solar power itself is green, the emissions from launching these enormous space-based power plants make it tricky to assess if it is actually better than ground-based alternatives—particularly because we don’t have a clear understanding of how emissions from rockets in the upper atmosphere affect climate change.
Here’s the roadmap: According to the authors, to make the case for SBSP close, we’ll need:
- Launch costs dropping to $500/kg (A Falcon 9 today costs about $3,000/kg)
- Infrastructure for frequent electric propulsion orbital transfer from LEO to GEO
- Hardware that lasts 15+ years
- Cheaper vehicles to service spacecraft and remove debris, on the order of $50-$100M
- The ability to drive down the cost of spacecraft through efficient manufacturing
And nothing happens in a vacuum (except in space, of course.) The study concludes that advancements in other areas of focus for NASA could be applied to SBSP, helping the tech get off the ground faster. Perhaps by the time the CalTech researchers working on novel phased-array solar panels have the kinks worked out, we’ll have the space infrastructure to build it on the cheap.
